Thermodynamic properties of in1-xbxp semiconducting alloys: a first-principles study
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González García, Alvaro | 2014
We have carried out first-principles total-energy calculations in order to study the
electronic structure and thermodynamic properties of In 1-xBxP semiconducting
alloys using the GGA and LDA formalisms within density functional theory (DFT)
with a plane-wave ultrasoft pseudopotential scheme. We have also taken into
account the correlation effects of the 3d-In orbitals within the LDA+U method to
calculate the band-gap energy. We use special quasirandom structures to
investigate the effect of the substituent concentration on structural parameter, band
gap energy, mixing enthalpy and phase diagram of In1-xBxP alloys for x = 0, 0.25,
0.50, 0.75 and 1. It is found that the lattice parameters of the In 1-xBxP alloys
decrease with B-concentration, showing a negative deviation from Vegard's law,
while the bulk modulus increases with composition x, showing a large deviation
from the linear concentration dependence (LCD). The calculated band structure
presents a similar behavior for any B-composition using LDA, PBE or LDA+U
approach. Our results predict that the band-gap shows a x-dependent nonlinear
behavior. Calculated band gaps also shows a transition from (Γ→Γ)-direct to
(Γ→Δ)- indirect at x = 0.611 and 0.566 for LDA and PBE functionals, respectively.
Our calculations predict that the In1-xBxP alloy to be stable at unusual high
temperature for both LDA and PBE potentials. © 2014 Elsevier B.V. All rights
reserved.
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